17. If the soul does not discern this great strength in itself, and if the particular devotion or vision help it not onwards, then it must not look upon it as safe. For though at first the soul is conscious of no harm, great harm may by degrees ensue; because, so far as I can see, and by experience understand, that which purports to come from God is received only in so far as it corresponds with the sacred writings; but if it varies therefrom ever so little, I am incomparably more convinced that it comes from Satan than I am now convinced it comes from God, however deep that conviction may be. In this case, there is no need to ask for signs, nor from what spirit it proceeds, because this varying is so clear a sign of the devil's presence, that if all the world were to assure me that it came from God, I would not believe it. The fact is, that all good seems to be lost out of sight, and to have fled from the soul, when the devil has spoken to it; the soul is thrown into a state of disgust, and is troubled, able to do no good thing whatever--for if it conceives good desires, they are not strong; its humility is fictitious, disturbed, and without sweetness. Any one who has ever tasted of the Spirit of God will, I think, understand it. 18. Nevertheless, Satan has many devices; and so there is nothing more certain than that it is safer to be afraid, and always on our guard, under a learned director, from whom nothing is concealed. If we do this, no harm can befall us, though much has befallen me through the excessive fears which possessed some people. For instance, it happened so once to me, when many persons in whom I had great confidence, and with good reason, had assembled together,--five or six in number, I think,--and all very great servants of God. It is true, my relations were with one of them only; but by his orders made my state known to the others. They had many conferences together about my necessities; for they had great affection for me, and were afraid I was under a delusion. I, too, was very much afraid whenever I was not occupied in prayer; but when I prayed, and our Lord bestowed His graces upon me, I was instantly reassured. My confessor told me they were all of opinion that I was deceived by Satan; that I must communicate less frequently, and contrive to distract myself in such a way as to be less alone. 19. I was in great fear myself, as I have just said, and my disease of the heart [12] contributed thereto, so that very often I did not dare to remain alone in my cell during the day. When I found so many maintain this, and myself unable to believe them, I had at once a most grievous scruple; for it seemed to me that I had very little humility, especially as they all led lives incomparably better than mine: they were also learned men. Why should I not believe them? I did all I could to believe them. I reflected on my wicked life, and therefore what they said to me must be true.